The idea of cooperative communications is rooted from relay communications. In cooperative communications, a user cooperates with other relay nodes to transmit information, ensuring communication between the user and a destination node. Relay-based next-generation network architecture has become the hot spot for research. By using cooperative transmission technology, it supports direct communication between a source node and a destination node. In addition, by introducing one or more relay nodes, it allows information sent from the source node to reach the destination node after being processed by the relay nodes in a certain manner. This multi-hop transmission manner bypasses obstacles that block electrical wave transmission such as buildings, overcomes the impact of large-scale fading to a certain extent, reduces path losses between sending and receiving terminals, and lowers the transmit power of the devices, thereby suppressing system interference and improving the signal-to-noise ratio of signals. In addition, because the destination node may perform receiving processing on signals from different transmitting nodes according to different combination manners, cooperative transmission may further apparently resist the impact of small-scale fading on channels, improving the transmission environment for signals to a certain extent and yielding different diversity gains.
Network coding is an information switching technology that integrates routing and coding. Its principle is to perform linear or non-linear processing on information received from each channel on each node on the network and forward the information to downstream nodes. If network coding is used, intermediate nodes on the network do not simply perform storage or forwarding, but encode received information and send the encoded information, thereby improving the network capacity and robustness. By combining network coding and cooperative communications in an organic manner, the system performance may be further improved.
In the existing technical solutions for combining network coding and cooperative communications, however, the receiving end uses an estimate obtained by decoding received signals for network decoding. In this manner, if more than one of the estimates at the receiving end is incorrect, all received information fails to be output through a network decoding way. According to the existing technical solutions, network coding is not fully utilized to yield diversity gains, and the system performance is not high.